Hi Eddie,
Can I just clarify what you need to do / what the main issue is?
Is it replacing colours with spot colours in a production press environment?
or is it specific driver issues associated with postscript?
I assume you have looked at your pre-press software / or plotter software to check for any postscript options?
Have you tried exporting your map using EPS as the output rather than PDF?
Happy to help where I can.
William.